| Full text | |
| Author(s): Show less - |
Ramirez, I.
[1, 2]
;
Melendez, J.
[3]
;
Bean, J.
[4]
;
Asplund, M.
[5]
;
Bedell, M.
[4]
;
Monroe, T.
[3]
;
Casagrande, L.
[5]
;
Schirbel, L.
[3]
;
Dreizler, S.
[6]
;
Teske, J.
[7, 8, 9]
;
Tucci Maia, M.
[3]
;
Alves-Brito, A.
[10]
;
Baumann, P.
Total Authors: 13
|
| Affiliation: | [1] Univ Texas Austin, Dept Astron, Austin, TX 78712 - USA
[2] Univ Texas Austin, McDonald Observ, Austin, TX 78712 - USA
[3] Dept Astron IAG USP, Sao Paulo - Brazil
[4] Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 - USA
[5] Australian Natl Univ, Res Sch Astron & Astrophys, Mt Stromlo Observ, Canberra, ACT - Australia
[6] Univ Gottingen, Inst Astrophys, D-37073 Gottingen - Germany
[7] Univ Arizona, Steward Observ, Dept Astron, Tucson, AZ 85721 - USA
[8] Carnegie Inst Sci, Dept Terr Magnetism, Washington, DC 20015 - USA
[9] Observ Carnegie Inst Washington, Pasadena, CA 91101 - USA
[10] Univ Fed Rio Grande do Sul, Inst Fis, BR-91501970 Porto Alegre, RS - Brazil
Total Affiliations: 10
|
| Document type: | Journal article |
| Source: | Astronomy & Astrophysics; v. 572, DEC 2014. |
| Web of Science Citations: | 58 |
| Abstract | |
Context. We are carrying out a search for planets around a sample of solar twin stars using the HARPS spectrograph. The goal of this project is to exploit the advantage offered by solar twins to obtain chemical abundances of unmatched precision. This survey will enable new studies of the stellar composition - planet connection. Aims. We determine the fundamental parameters of the 88 solar twin stars that have been chosen as targets for our experiment. Methods. We used the MIKE spectrograph on the Magellan Clay Telescope to acquire high resolution, high signal-to-noise ratio spectra of our sample stars. We measured the equivalent widths of iron lines and used strict differential excitation/ionization balance analysis to determine atmospheric parameters of unprecedented internal precision: sigma(T-eff) = 7K, sigma(log g) = 0.019, sigma({[}Fe/H]) = 0.006 dex, sigma(v(t)) = 0.016 km s(-1). Reliable relative ages and highly precise masses were then estimated using theoretical isochrones. Results. The spectroscopic parameters we derived are in good agreement with those measured using other independent techniques. There is even better agreement if the sample is restricted to those stars with the most internally precise determinations of stellar parameters in every technique involved. The root-mean-square scatter of the differences seen is fully compatible with the observational errors, demonstrating, as assumed thus far, that systematic uncertainties in the stellar parameters are negligible in the study of solar twins. We find a tight activity-age relation for our sample stars, which validates the internal precision of our dating method. Furthermore, we find that the solar cycle is perfectly consistent both with this trend and its star-to-star scatter. Conclusions. We present the largest sample of solar twins analyzed homogeneously using high quality spectra. The fundamental parameters derived from this work will be employed in subsequent work that aims to explore the connections between planet formation and stellar chemical composition. (AU) | |
| FAPESP's process: | 13/25008-4 - Chemical composition of solar-type stars |
| Grantee: | Lucas Alexandre Schirbel |
| Support Opportunities: | Scholarships in Brazil - Scientific Initiation |
| FAPESP's process: | 12/24392-2 - High precision spectroscopy: impact in the study of planets, stars, the galaxy and cosmology |
| Grantee: | Jorge Luis Melendez Moreno |
| Support Opportunities: | Research Projects - Thematic Grants |